1. Field of the Invention
This invention pertains to the art of fiber reinforced solids.
2. Description of the Prior Art
Weaving is a prehistoric art. Its usual product is a layer of two classes of threads; reeds are woven e.g. in baskets, in a variety of patterns, but still in a single layered rather than a thick multilayered structure. In general, any initially plastic material applied to such woven structures is believed to having been for sealing or protection rather than the formation of a reinforced solid, despite the known use of unwoven straw to reinforce brick clay in time of the Egyptian oppression of the Hebrews.
Kruse et. al (U.S. Pat. No. 3,322,868) exemplifies a solid woven structure having three mutually orthogonal classes of threads along Cartesian axes, intended for impregnation with resin or similar suitable material. No prior art is known to the applicant in which axial, radial, and circumferential threads are woven to form a structure of arbitrary thickness, with completely free choice of the relative numbers of threads of these three classes.
Publications reported in a novelty search of this invention are:
D. Robbins, Structural Components Produced by Modified Weaving Techniques, Textile Institute and Industry, March 1970.
R. S. Barton, A Three-Dimensionally Reinforced Material, SPE Journal, Volume 24, May 1968.
Weaving Tough Fabric with a New Dimension, Business Week, Aug. 31, 1968.
P. D. Emerson, Modern Developments in Three-Dimensional Fabrics, Modern Textiles, November 1969.
The last named reference describes a so-called "porcupine" structure in which radial threads extend from a central mandrel on which a fabric is woven, or are even drawn through the fabric after it is woven. They are not woven in the fabric in the sense that they are interlocked with other threads, but are apparently (so far as the description permits one to speculate) somewhat in the same situation as knitting needles in a piece of knitting in process.